As is well known, many machines, such as looms, are not directly supplied with yarn from a bobbin, cop, spool or the like, but from a spool such a yarn reaches the utilization machine after being previously wound up on an apparatus, thereat forming a magazine or supply of yarn, which is then supplied to the utilization machine with a constant controlled tension, or at constant rates.
The prior art apparatus comprises a drum, to one end of which yarn windings are wound, the yarn being drawn off from the other end of the drum. Rigid oscillating mechanical members are then provided and are effective on the yarn windings wound up on the drum, causing the translation at that end of the drum, whereat they are supplied, to the other end where the yarn is drawn off. In some apparatus, such as those disclosed in German Pat. No. 2,301,416, U.S. Pat. No. 3,796,386, French Pat. No. 1,285,954 or corresponding German Pat. No. 1,191,197, the yarn is drawn off through a hole or bore centrally of the drum, on which the windings are wound.
Mechanical members of different nature are known for translating the yarn windings along the outer surface of the drum. According to the disclosure in the above mentioned patents, U.S. Pat. Nos. 3,419,225 and 2,625,340 and still many other patents, adjacent that end of the drum where the yarn is wound, provision is made for a disc or plate oscillating with respect to the drum, this plate having an arc on its surface which is always in contact with a length or section of the winding closest thereto.
The plate oscillates about an axis inclined relative to the drum axis, so that the contacting zone between the plate and yarn winding adjacent thereto will continuously vary throughout the drum periphery. Thus, the plate urges or pushes the winding ahead, leaving a free space wherein another winding is continuously distributed. The winding being pushed away by the plate, in turn pushes away the winding adjacent thereto, the latter pushing away the next winding and so on, causing a simultaneous displacement of the entire package of windings wound up on the drum.
This winding translation system suffers from serious disadvantages consisting, for example, in that with particular yarns the windings tend to overlap, the windings tend to bind against one another should the yarn be of pile nature, and that, should the yarn break at any location, the windings loosen and overlap, making it difficult to find the free end of the broken yarn.
Other systems are also known for yarn displacement on the drum, such as that disclosed in U.S. Pat. No. 1,052,212, wherein the apparatus comprises two sets of circumferential bars and members for radially and axially moving each set of bars relative to the other set, so that each set of bars alternately picks up the yarn wound up about the sets of bars, axially displaces the yarn and lets it go on the other set of bars. Also this yarn winding displacement system has disadvantages consisting, for example, in that the windings tend to freely drop or fall down and overlap (which is avoided by imparting a high tension to the incoming yarn on the apparatus), there is no control on the position of the yarn windings and also, should the yarn break, the windings tend to drop or fall down and it is difficult to find the free end of the broken yarn.